That impenetrable fortress of online gaming, World of Warcraft, has made a concession to the free-to-play hordes that gather in an effort to chip away at the empire: WoW's new Starter Edition is itself free.

Replacing a more customary 14-day trial and scrubbing its time limit, the Starter Edition nonetheless carries over the trial's restrictions.

In place of a time limit is instead a cap that halts character progression at level 20 out of a possible 85.

Coincidentally, it takes about two weeks playing a couple of hours each day to reach level 20, but on the other hand, those with the Starter Edition can grind out as many sub-20 characters as they like.

So what can't they do? Well, the social experience is significantly diminished: there's no voice or public chat, no guilds, no item trading (a key part of WoW's internal economy), and Starter users are prevented from creating or joining parties that contain members over the level 20 threshold.

Oh, and there's a wealth limit of 10 gold - but that's actually a decent amount in WoW terms.

For now at least, WoW remains steadfastly focused on converting new players into paid subscribers, bundling in the Burning Crusade expansion for those that pony up.

Other massively multiplayer games that become free-to-play - Lord of the Rings Online, Champions Online, and (soon) LEGO Universe and City of Heroes - make money by means of an in-game shop that offers extra items and quests, with optional premium memberships taking the place of a subscription tier.

Some, like Allods Online and Vindictus, launch as free-to-play from the off; Guild Wars 2 will require a one-time retail purchase only; and then there are the brave few, such as RIFT, that pursue a fully fledged subscription model in an effort to beat the 12-million subscriber WoW at its own game.